CHARLOTTE, N.C. - More troubling news erupted from the financial-services sector yesterday as Wachovia, PNC and Bank of America warned of bigger-than-expected write-downs and hinted that fourth-quarter results could be disappointing.

Wachovia Corp. doubled its estimate of loan-loss provisions to about $1 billion for the fourth quarter, while the chief executive officer of Bank of America Corp. pointed to higher write-downs than previously forecast and said he expected credit-market turbulence to extend into 2008. Both banks are based in Charlotte and have significant shares of the Philadelphia banking market.

A third major bank, PNC Financial Services Group, of Pittsburgh, said the money it would set aside to cover bad loans for the fourth quarter would be more than twice as much as in the third quarter.

Wachovia has the largest share of the Philadelphia market, with 21 percent of the area's deposits, while PNC has 8.2 percent and Bank of America has 6 percent.

Yesterday's disclosures come as a number of the nations' banks have forecast increasing credit losses in the wake of last summer's subprime-mortgage crisis.

In a previous filing with the Securities and Exchange Commission last month, Wachovia said it expected to record a loan-loss provision in the fourth quarter of between $500 million and $600 million.

But in a discussion with financial analysts yesterday in New York, chief executive Ken Thompson said fourth-quarter losses from commercial and consumer mortgages, leveraged finance, and structured products, including subprime-backed mortgage securities, had reached about $1.4 billion, similar to the level seen in the third quarter.

Wachovia shares fell $1.42 to close at $40.53 in New York Stock Exchange trading yesterday, Bank of America shares lost $1.22 to close at $43.43, and PNC shares were down $2.51 at $68.25.

Bank of America said it expected to take a provision expense of $3.3 billion in the fourth quarter, and it warned that write-downs on mortgage-related securities could grow, adding to fears that the nation's housing and mortgage-lending slump might exact a greater toll than in the third quarter, when industrywide write-downs topped $46 billion.

PNC Financial Services said its adjusted provision for credit losses was expected to be about $110 million in the fourth quarter, up $45 million from the previous quarter.